Tree harvesting apparatus

ABSTRACT

An improved tree harvesting method is performed by a machine which includes a pair of booms mounted on a vehicle. A clamp assembly is mounted on a first boom for gripping a standing tree which is then severed close to the ground by a shear assembly which is also mounted on the first boom. The severed tree is positioned relative to a delimbing mechanism mounted on the second boom by moving the clamp assembly to place the tree in a generally horizontal position. The tree and clamp assembly are then pivoted about a longitudinal axis of the first boom to position the tree for engagement by the delimbing mechanism. The severed tree is delimbed by extending the second boom to move the delimbing mechanism along the trunk of the tree while the tree is gripped by the clamp assembly. When the delimbing mechanism senses or encounters a portion of the tree having a predetermined cross-sectional dimension, a topping assembly is automatically operated to top the tree by severing the tree trunk under the influence of movement of the topping assembly along the tree trunk. The log formed by delimbing and topping the severed tree is then deposited in a bunk assembly for transporting. The bunk assembly advantageously includes a support member or roller which is raised upon operation of the bunk assembly to an open condition to at least partially disengage logs from the bunk assembly.

This is a division of application Ser. No. 888,746, filed Dec. 29, 1969,now U.S. Pat. No. 3,796,241.

The present invention relates to a new and improved method and apparatusfor harvesting trees.

There are many known types of tree harvesting machines, such as the onedisclosed in U.S. Pat. No. 3,353,575. While they have been more or lesssatisfactory in operation, these known machines have proven to besomewhat unsatisfactory for various reasons. The present invention isdirected to a new and improved tree harvesting machine which is of apractical design, and capable of felling and processing trees in anefficient reliable manner.

It is an object of this invention to provide a new and improved treeharvesting machine which is readily maneuverable in forested areas,capable of relatively high speed operation, and operable to transportlogs out of a forested area.

Another object of this invention is to provide a new and improved methodand apparatus for harvesting trees wherein the trees are gripped with aclamp assembly and severed by a shear mechanism mounted on a first boomand are then delimbed and topped by apparatus mounted on a second boomwhile the tree is gripped by the clamp assembly on the first boom.

Another object of this invention is to provide a new and improved treeharvesting apparatus including a first boom having apparatus mountedthereon for gripping and severing a tree close to the ground and asecond boom having a delimbing and topping mechanism mounted thereon fordelimbing and topping a tree gripped by the apparatus on the first boom.

Another object of this invention is to provide a new and improved treeharvesting method and apparatus for delimbing a tree and topping thetree in response to a sensing of a portion of the tree having apredetermined cross-sectional dimension.

Another object of this invention is to provide a new and improved methodand apparatus for topping a tree under the influence of relativemovement in an axial direction between a tree and a topping assembly.

Still another object of this invention is to provide a new and improvedtree harvesting apparatus including a bunk assembly from which logs areat least partially disengaged by operation of the bunk assembly to anopen condition.

Yet another object of this invention is to provide a new and improvedtree harvesting apparatus having a plurality of telescoping boomsections with a bearing assembly between the boom sections wherein thebearing assembly includes means for yieldably supporting the boomsections to enable limited movement to occur between the boom sectionsin a direction transverse to their direction of telescopic movement.

Another object of the present invention is the provision of a delimbingmechanism carried on a telescoping boom section which extends in adelimbing stroke and wherein the delimbing mechanism is operated to anopen condition during the last part of the delimbing stroke of thetelescoping boom.

Still another object of the present invention is the provision of atopping mechanism carried on a telescoping boom section and which isactuated in response to a sensing mechanism sensing a predetermined treediameter and wherein means is provided for actuating the toppingmechanism during the last part of the extension of the boom, if the treediameter is somewhat greater than the predetermined diameter.

These and other objects and festures of the invention will become moreapparent upon a consideration of the following description taken incombination with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a tree harvesting machineconstructed in accordance with the present invention, the treeharvesting machine being shown delimbing a tree held by a clamp assemblyon a first boom with a delimbing mechanism on a second boom;

FIG. 2 is a schematic illustration depicting the gripping of a standingtree with the clamp assembly on the first boom;

FIG. 3 is a schematic illustration, similar to FIG. 2, depicting thepositioning of a severed tree for engagement by the delimbing mechanismmounted on the second boom;

FIG. 4 is a schematic illustration of the delimbing of a tree byextending the second boom to move the delimbing mechanism along thetrunk of the tree;

FIG. 5 is a schematic illustration depicting the depositing of a log,formed by delimbing and topping a tree, in a bunk or clamp assemblywhich grips logs while they are dragged or pulled by the tree harvestingmachine;

FIG. 6 is an enlarged schematic plan view illustrating the relationshipbetween the two booms;

FIG. 7 is a schematic elevational view further illustrating thestructure of the booms;

FIG. 8 is an elevational view illustrating the relationship between atree shear assembly mounted on the first boom and the trunk of a tree tobe severed by the shear assembly;

FIG. 9 is a partially broken away sectional view, taken generally alongthe line 9--9 of FIG. 8, further illustrating the construction of thetree shear assembly;

FIG. 10 is a sectional view, taken generally along the line 10--10 ofFIG. 6, illustrating an assembly for pivoting the clamp assembly and atree gripped thereby about a longitudinal axis of the first boom andinto engagement with the delimbing mechanism mounted on the second boom;

FIG. 11 is an enlarged fragmentary sectional view, similar to FIG. 10,illustrating the relationship between telescoping sections of the secondboom and bearing assemblies for facilitating relative movement betweenthese boom sections;

FIG. 12 is a partially broken away fragmentary sectional viewillustrating the construction of the delimbing mechanism and theconstruction of the topping assembly;

FIG. 13 is a fragmentary elevational view, taken generally along theline 13--13 of FIG. 12, further illustrating the relationship betweenthe delimbing mechanism and the topping assembly;

FIG. 14 is a schematic illustration of a cable arrangement for extendingthe second boom;

FIG. 15 is a schematic illustration depicting the relationship betweenthe trunk of a tree, blades of the topping assembly, and the delimbingmechanism as the delimbing mechanism is moved along the tree trunk;

FIG. 16 is a schematic illustration depicting the relationship betweenthe blades of the topping assembly and the tree trunk as the blades arereleased to effect a topping of the tree;

FIG. 17 is a schematic illustration of the severing of the tree trunk bythe blades of the topping assembly;

FIG. 18 is an elevational view of a bunk assembly for gripping logs toenable them to be dragged or pulled by the tree harvesting machine;

FIG. 19 is an elevational view, taken generally along the line 19--19 ofFIG. 18, illustrating the relationship between the bunk assembly and asupport platform;

FIG. 20 is an elevational view, generally similar to FIG. 19,illustrating the bunk assembly in an open condition in which a supportmember or roller at least partially disengages the logs from the bunkassembly;

FIG. 21 is a schematic view illustrating a mechanism for opening thedelimber;

FIG. 22 is a view of a mechanism for triggering the topping of a treeduring the last part of the extension of the second boom;

FIG. 23 is a fragmentary sectional view through the outer portion of thebooms and taken approximately along lines 23--23 of FIG. 25;

FIG. 24 is another view of the mechanism for triggering topping of atree; and

FIG. 25 is a fragmentary longitudinal sectional view of a portion of thebooms illustrating still another part of the mechanism of FIG. 22.

A preferred specific embodiment of a tree harvesting machine 30constructed in accordance with the present invention is illustrated inFIG. 1. The tree harvesting machine 30 is operable to cut or sever astanding tree and to delimb and top the severed tree to form a log. Whena number of trees has been so processed, the resulting logs aretransported to another location by the tree harvesting machine 30.

The tree harvesting machine 30 includes an articulated vehicle 32 havingan operator's cab 34. Suitable vehicular controls 36 are located in theoperator's cab. In addition to the controls 36, other controls (notshown) are provided for controlling the operation of first and secondbooms 40 and 42. The controls for the first and second booms aresupported for rotational movement with the seat 70 for the operator, sothat the controls are readily operable in all positions of the seat. Anysuitable structural arrangement may be provided to allow for movement ofthe controls and seat. A clamp assembly 46 for gripping a tree and ashear assembly 48 for severing the trunk of a tree are mounted on thefirst boom 40. A tree delimbing mechanism 50 and a tree topping assembly52 are mounted on the second boom 42. The delimbing mechanism 50 andtopping assembly 52 are movable along a severed tree gripped by theclamp assembly 46 to delimb and top the tree. In addition, a bunk orclamp assembly 56 is mounted on the vehicle 32 to grip logs 58 formed byoperation of the tree harvesting machine 30.

The harvesting or processing of a standing tree 62 (FIG. 2) is initiatedby pivoting the booms 40 and 42 toward the tree 62 about a vertical axisthrough the operator's cab 34. This pivoting movement of the booms 40and 42 is effected by a hydraulic motor 66 mounted on a roof 68 of theoperator's cab 34 (FIGS. 6 and 7). It should be noted that the pivotingmovement of the booms 40 and 42 about the vertical axis results in theoperator's seat 70 FIG. 2), which is connected to the booms by a frame71, being moved with the booms so that the operator faces toward theoperating ends of the booms. The booms 40 and 42 are then pivoteddownwardly about a horizontal axis by extending piston and cylinderassemblies 72 and 74 to position the clamp assembly 46 at the base of atrunk 80 of the upright tree 62. The clamp assembly 46 is moved intoengagement with the trunk 80 of the tree by operation of a cylinderassembly 82 which pivots a mounting arm 84 relative to the boom 40 tobring clamp arms 86 and 88 into engagement with the trunk 80 of thetree. An actuator cylinder 92 (see FIG. 6) is operable to move the clamparms 86 and 88 into secure gripping engagement with the trunk 80 of thetree.

The trunk 80 of the tree is then severed by the tree shear assembly 48(see FIGS. 2, 8 and 9). The tree shear assembly 48 is mounted directlybeneath the clamp assembly 46 and includes a pair of rotatably mountedarms 96 and 98 having blades 100 and 102 (see FIGS. 8 and 9). The blades100 and 102 are mounted on the arms 96 and 98, respectively, by suitablefasteners 104 which enable the blades 100, 102 to be disconnected fromthe associated arms and replaced if and when they become dull or worn.The arms 96 and 98 are pivoted between an open position (see FIG. 2) anda closed position (FIG. 9) by operation of a piston and cylinderassembly 104. The piston and cylinder assembly 104 is advantageouslymounted above the blades 100 and 102 and the blades can shear or severthe trunk of the tree relatively close to the ground in a mannerillustrated in FIG. 8.

Once the trunk 80 of the tree has been severed by operation of the shearassembly 48, the upright tree is moved to a generally horizontalposition for delimbing (see FIG. 3). The severed tree 62 is positionedfor delimbing by first pivoting the boom 40 upwardly from the positionillustrated in FIG. 2 to raise the severed end of the tree 62 from itsassociated stump. The hydraulic motor 66 is then operated to swing theboom 42 about a vertical axis (see FIG. 3). In addition, a movablesection 105 of the boom 40 is retracted relative to a fixed housing 106by a piston and assembly 107 (FIG. 1) to position the severed end of thetree adjacent to the rear of the articulated vehicle 32. The piston andcylinder assembly 82 is then extended to pivot the arm 84 inwardly toorient the tree 62 in a generally horizontally extending position (FIG.3) in which it is generally parallel to the booms 40, 42.

The horizontally extending tree 62 is then pivoted about alongitudinally extending axis of the first boom 40 by operation of apositioning assembly 108 (FIG. 10). The positioning assembly 108includes a piston and cylinder assembly 109 which is extended to rotatean actuator arm 110 secured to the housing 106. Extending the piston andcylinder assembly 109 rotates the arm 110 about a longitudinal axis ofthe boom 40, from the position shown in solid lines in FIG. 10 to theposition shown in dashed lines in FIG. 10. This movement of the arm 110rotates the boom 40 to move the clamp assembly 46 and the tree 62upwardly from the position illustrated in FIG. 3 to the position shownin FIG. 1 so that the horizontally extending tree 62 can be engaged by adelimbing mechanism 50. The tree 62 is then delimbed by the delimbingmechanism 50 and topped by the topping assembly 52 while being held bythe clamp assembly 46.

The delimbing mechanism 50 (see FIGS. 12 and 13) includes a pair of arms126 and 128 which are pivotally mounted at 130 and 132 (FIG. 13) on acentral support section 134 which is fixedly connected to a frame 138.The delimbing members or arms 126 and 128 are urged inwardly intoengagement with the trunk 80 of a tree by a biasing assembly 142. Thisensures that the arms 126 and 128 engage the trunk 80 of the tree eventhough the diameter of the trunk decreases along the tree in the mannerillustrated schematically in dashed lines in FIG. 13.

The biasing assembly 142 (see FIG. 12) includes a spring 148 located ina cylindrical housing 152 between an end wall 154 of the housing and apiston or head element 156. The piston 156 is pivotally connected to alink 160 of a linkage arrangement 166 for interconnecting the biasingassembly 142 and the delimbing members 126 and 128. The spring 148 urgesthe piston 156 toward the left, as viewed in FIG. 12, to cause the link160 to urge an actuator lever 170 in a generally clockwise directionabout a pivot connection 174. The actuator lever 170 is connected bylinks 176 and 178 to the delimbing members 126 and 128 (FIGS. 12 and13). When the actuator lever 170 is moved in a clockwise direction, asviewed in FIG. 12, under the influence of the biasing assembly 142, thelink 176 is moved toward the left, as viewed in FIG. 13, to pivot thedelimbing member or arm 126 inwardly about the pivot connection 130.similarly, the clockwise movement of the actuator lever 170, as viewedin FIG. 12, pulls the link 178 towards the right, as viewed in FIG. 13,to pivot the delimbing member or arm 128 inwardly about the pivotconnection 132.

When the boom 42 is in the retracted position of FIGS. 6 and 7, anoperator member 186 extends into the housing 152 of the biasing assembly142 to press the piston 156 toward the right as viewed in FIG. 12against the influence of the spring 148. This rightward movement of thepiston 156 causes the linkage arrangement 166 to pivot the delimbingarms or members 126 and 128 outwardly to the open position of FIG. 13 toenable the trunk 80 of a severed tree to be positioned between thedelimbing members 126 and 128 in the manner illustrated in dashed linesin FIG. 13.

When the severed tree 62 is positioned relative to the delimbingmechanism 50 by the previously described operation of the boom 40 andclamp assembly 46, the boom 42 is extended outwardly to move thedelimbing mechanism 50 along the horizontal trunk 80 of the tree 62 inthe manner illustrated schematically in FIG. 4. To provide for thismovement of the delimbing mechanism 50, the boom 42 includes a pluralityof movable sections 188, 190 and 192 and a fixed section 194 which aremounted in a telescoping relationship with each other (see FIGS. 1, 4and 11). Extending the boom 42 is facilitated by bearing elements 200(FIG. 11) located between the sections 188, 190, 192 and 194 of thetelescoping boom.

The bearing elements 200 each include a resilient or yieldable base orlayer 212 formed of a suitable elastomeric or rubber-like material. Thebase 212 is fixedly connected to one of the sections 190, 192 or 194. Ametallic bearing element 216 is mounted on each of the yieldable basesor layers 212. Each of the bearing elements 216 is slidably engaged bythe next adjacent inner section of the telescoping boom whenever theboom is either extended or retracted. The yieldable base 212 enables themovable sections 188, 190 and 192 to deflect transversely to thedirection in which they are being extended or retracted and also enablesthem to rotate to a certain extent about the longitudinal axis of theboom 42. Bearing elements, similar to the bearing elements 200, areprovided between the fixed housing 106 and telescoping section 105 ofthe boom 40 to facilitate extending and retracting this boom.

It is contemplated that many different types of drive arrangements couldbe used to extend the boom 42. One such drive arrangement is a cableassembly 220, illustrated schematically in FIG. 14, which is operable toeffect telescopic movement between the sections 188, 190, 192 and 194 ofthe boom 42. The cable assembly 220 includes an actuator assembly 224mounted on the fixed outer section 194 of the boom 42. The actuatorassembly 224 is expandable to extend the boom 42 and retractable tocontract the boom. The cable assembly 220 includes a pair of pulleys 228and 230 which are connected to opposite ends of the actuator assembly224. The pulleys 228 and 230 are moved apart by extending the actuatorassembly 224.

Moving the pulleys 228 and 230 apart pulls a cable 234 to effect outwardmovement of the boom section 192. The cable 234 is connected at an outerend 236 to the fixed section 194 of the boom 42 and at an inner end 238to the movable section 192 of the boom. As the actuator assembly 224 isextended, the cable 234 is pulled toward the right, as viewed in FIG.14, to move the boom section 192 outwardly relative to the boom section194. This outward movement of the boom section 192 results in the boomsection 190 being moved outwardly by a cable 242. The cable 242 isfixedly connected at an outer end 244 to the fixed boom section 194 andextends around an idler pulley 248 mounted on the movable boom section190. An inner end of the cable 242 is connected at 250 to the boomsection 190. Thus, upon outward movement of the section 192 of the boom40, the cable 242 causes the boom section 190 to move outwardly.Contemporaneously therewith, the inner boom section 188 is movedoutwardly relative to the boom section 190 by a cable 254 which isconnected at an outer end 256 to the boom section 192 and extends aroundan idler pulley 260 mounted on the boom section 190 to an inner end 262secured to the boom section 188. Of course, outward movement of the boomsection 190 causes the pulley 260 to move outwardly relative to the boomsection 192 to thereby move the innermost boom section 188 outwardlyrelative to the boom section 190.

The boom 42 is retracted in a similar manner by contracting theactutator assembly 224. Thus, the cable drive assembly 220 includes acable 270 which extends around a pulley 272 which is moved to the left,as viewed in FIG. 14, by contracting the actuator assembly 224. Sincethe cable 270 is fixed at 276 to the outer boom section 194 and issecured at 280 to the boom section 192, when the piston and cylinderassembly 224 is contracted, the boom section 192 is moved toward theleft. A cable 284 extends from a fixed outer connection 286, around apulley 288 mounted on the boom section 192, to the inner connection 250on the boom section 190. Therefore, leftward movement of the boomsection 192 relative to the outer section 194 of the boom 42 results inthe section 190 of the boom being pulled toward the left, as viewed inFIG. 14, by the cable 284. Similarly, a cable 292 is connected at anouter end 294 to the movable boom section 192 and extends around apulley 298 to an inner connection 300 on the inner boom section 188.Therefore, inward movement of the boom section 190 results in the innerboom section 188 being retracted by the cable 292.

It should be noted that although a specific cable drive arrangement 220has been illustrated schematically in FIG. 14, it is contemplated thatother cable drive arrangements or suitable hydraulic drive arrangementscould be utilized to extend and retract the boom 42. Since such cableand hydraulic drive arrangements are well known to those skilled in theart, it is believed that a further description of the cable drivearrangement 220 is not necessary at this time.

As the delimbing mechanism 50 is moved outwardly by extending the boom42, a knife edge 302 formed on the central support portion 134 of thedelimbing mechanism 50 (see FIGS. 12 and 13) and knife edges 304 and 306formed on the delimbing members 126 and 128 are impacted against limbsor branches 308. This impacting severs the branches adjacent the trunk80 of the tree to thereby strip or remove the branches from the trunk ofthe tree in the manner illustrated schematically in FIG. 4. During thisoutward movement of the delimbing mechanism 50, the biasing unit 142operates the linkage arrangement 166 to press the delimbing members 126and 128 into engagement with the trunk 80 of the tree even though thediameter or cross-sectional dimension of the trunk decreases as thedelimbing mechanism 50 moves outwardly along the trunk.

After the delimbing mechanism 50 has been moved outwardly along thetrunk 80 of the tree 62 until it is adjacent to a portion of the trunk80 having a diameter at which it is desired to top or sever the trunk80, the topping assembly 52 is automatically operated to top the tree.The topping assembly 52 includes a pair of pivotally mounted blades 310and 312 (FIGS. 12 and 13) which are pivotally mounted at 314 and 316 forinward movement from an outermost position illustrated in solid lines inFIG. 12 to a severing position illustrated in dashed lines in FIG. 12.The blades 310 and 312 are urged inwardly toward the trunk 80 of thetree 62 by a biasing spring 330. The biasing spring urges an actuatorarm 332 connected to the blade 312 in a counterclockwise direction, asviewed in FIG. 12. The blades 310 and 312 are interconnected by a link334 which extends between actuator arms 336 and 338 to urge the blade310 in a clockwise direction, as viewed in FIG. 12.

When the delimbing mechanism 50 is moving along the trunk 80 of the tree62, the blades 310 and 312 are held in a spaced apart relationship withthe trunk 80 of the tree (see FIGS. 12 and 15). To hold the blades 310and 312 in this position against the urging of the biasing spring 330, aconnector pin 344 on the delimbing member 128 engages a leading knifeedge portion 350 of the blade 310. As the delimbing mechanism 50 movesoutwardly along the trunk 80 of the tree, the diameter ofcross-sectional dimension of the trunk decreases. As the cross-sectionaldimension or diameter decreases, the delimbing members 126 and 128 aremoved inwardly under the influence of the biasing assembly 142. Thisinward movement of the delimbing members 126 and 128 results in theknife edge portion 350 of the blade 310 clearing a rearward end portionof the pin 344 to enable the blades 310 and 312 to be pivoted intoengagement with the trunk 80 of the tree in the manner illustratedschematically in FIG. 16.

Continued movement of the delimbing mechanism 50 and topping assembly 52along the trunk of the tree causes the knife edges 350 and 354 on theblades 310 and 312 to be wedgingly forced into the trunk 80 to sever thetrunk in the manner illustrated schematically in FIG. 17. Thus, thedelimbing members 126 and 128 effectively sense the diameter of the treetrunk 80 as they are moved along the tree trunk and release the blades310 and 312 when a predetermined diameter is encountered. The releasedblades then penetrate into the tree trunk 80 under the influence ofcontinued outward movement of the topping assembly 52 to sever the treetrunk (FIG. 17). Since the delimbing members 126 and 128 sense thediameter of the tree trunk and effect operation of the topping assembly52 when a predetermined trunk diameter is encountered, the toppingassembly 52 is operated automatically at the proper time without anoperator of the tree harvesting machine performing a control operation.This tends to speed up operation of the tree harvesting machine andminimizes the degree of skill required by the operator.

When the boom 42 is being retracted, an operator member 360 (FIG. 12) onthe section 190 of the boom assembly, is moved into engagement with theblade 310. Continued retraction of the boom 42 pivots the blades 310 and312 outwardly to the open condition. Continued retraction of the boom 42also brings the operator member 186, which is mounted on the section 190of the boom, into engagement with the piston 156. Therefore, thedelimbing members 126 and 128 are swung outwardly after the knife edge350 on the blade 310 has cleared the pin 344. Continued outward movementof the delimbing members 126 and 128 results in the delimbing membersbeing swung to a position in which the pin 344 will hold the knifeblades 310 and 312 from the trunk of the next tree to be delimbed.

The delimbed and topped tree 62 forms a log 58 (see FIG. 5) which isplaced in the bunk assembly 56 by operation of the boom 40 and clampassembly 46. To accomplish this, the boom 40 is rotated in the directionof the arrow in FIG. 5 by operation of the positioning assembly 108 fromthe position shown in dashed lines in FIG. 10 to the position shown insolid lines so that the end of the log 58 is clear of the delimbingmechanism 50. The boom 40 is then pivoted downwardly about a horizontalaxis and the clamp assembly 48 swung outwardly by operation of thepiston and cylinder assembly 82 to lower the end of the log into thebunk assembly 56. Finally, the clamp assembly 46 is operated to the openposition to release the log 58. The boom assemblies 40 and 42 are thenoperated in the manner previously explained to grip, sever, delimb andtop the next tree to be harvested.

When a plurality of logs 58 have been placed in the bunk assembly 56,clamp arms 370 and 372 are pivoted to the closed condition illustratedin FIG. 18 by extending an actuator cylinder assembly 372 which operatesa linkage arrangement 376 extending between the clamp arms 370 and 372.The linkage arrangement 376 moves the clamp arms 370 and 372 in themanner fully disclosed in application Ser. No. 822,906 filed by Symonset al on May 8, 1969 and entitled Logging Apparatus. In the closedcondition, the clamp arms 370 and 372 press the logs 58 inwardly anddownwardly toward a knife edge 380 extending between the clamp arms 370and 372. The knife edge 380 penetrates the logs 58 to securely retainthe logs against sliding movement relative to the bunk assembly 56 asthe logs are being pulled or dragged by the vehicle 32.

The bunk assembly 56 includes a frame 384 to which the clamp arms 370and 372 are pivotally connected by mounting pins 386 and 388. The frame384 has an acurate bottom or base 390 which rests on a platform 392 onthe vehicle 32 and is pivotally connected with a fixed mounting bracket394 by a link 396 (FIG. 19). The link 396 enables the bunk assembly 56to move sidewardly between the pair of stop members, only one stopmember 398 being shown, while the vehicle 32 is pulling or transportingthe logs 58.

When the tree harvesting machine 30 is moved to a location where thelogs 58 are to be dropped or dumped, it is necessary to disengage thelogs from the knife edge 380. To accomplish this, cam elements 402 and404 connected with the clamp arms 370 and 372 are pivoted about the pins386 and 388 respectively as the clamp arms are moved to the openposition. This pivoting movement of the cam elements 402 and 404 bringsthem into engagement with the platform 392 to rock the frame 384upwardly and rearwardly in the manner illustrated in FIG. 20. Thisupward and rearward rocking or pivoting of the frame 384 raises asupport member or roller 408 into engagement with the logs 58 to liftthem up off the knife edge 380 (see FIG. 20). This disengages the logs58 from the knife edge 380 so that they can be dropped or dumped bymerely pulling the vehicle ahead and moving them along the roller 408.

Once the logs have been dumped, the tree harvesting machine 30 is drivenback to a work area to process or harvest other trees. During movementof the vehicle 32 to and from a work area, it is important that thebooms 40 and 42 and the apparatus mounted thereon be as compact aspossible to facilitate maneuvering the tree harvesting machine 30. Thepreviously described telescoping construction of the booms 40 and 42enables the longitudinal extent of the booms to be minimized. Inaddition, the clamp assembly 46 and tree shear 48 are positionable in atraveling position between the booms 40 and 42 inwardly of the delimbingmechanism 50 and topping assembly 52 (see FIG. 6). When the clampassembly 46 and tree shear 48 are in this traveling position, they areout of the way and provide a minimum of interference to the operator'svision.

In view of the foregoing description, it can be seen that the treeharvesting machine 30 includes a pair of telescopic booms 40 and 42. Theclamp assembly 46 is mounted on the boom 40 and is operable to engagethe trunk of a standing tree which is then severed by operation of thetree shear 48. The upright tree 62 is moved to a generally horizontalposition (FIG. 3) by moving the clamp assembly 46 upwardly and inwardlytoward the vehicle 32. The clamp assembly 46 is then pivoted about thelongitudinal axis of the boom 40 to move the trunk 80 of the tree intoengagement with the delimbing mechanism 50 The horizontal tree 62 isthen delimbed by extending the boom 42 to move the delimbing mechanism50 outwardly along the trunk of the tree while it is securely gripped bythe clamp assembly 46.

When the delimbing members 126 and 128 sense that the trunk 80 has apredetermined relatively small diameter at which the tree 62 is to betopped, the blades 310 and 312 of the topping assembly 52 are releasedfor movement into engagement with the trunk of the tree in the mannerillustrated schematically in FIG. 16. Continued movement of the toppingassembly 52 and delimbing mechanism 50 outwardly along the trunk of thetree results in the blades 310 and 312 being forced into the trunk ofthe tree to sever or top the tree. The log 58 resulting from thedelimbing and topping of the tree 62 is then deposited in the bunkassembly 56 so that it can be pulled or dragged from the place where thetree was harvested by operation of the vehicle 32.

As described above, the tree harvesting apparatus illustrated in FIGS.1-20 includes a delimbing mechanism which moves outwardly along the treein a word stroke to effect delimbing of a tree. The delimbing mechanismalso triggers the topping of the tree. The topping action is effected bythe movement of the pin 344, which is carried by the delimbing arm 306,out of engagement with the topping blade 310 so that the topping blades310, 312 may engage the tree and top the tree. This, of course, iseffected when the diameter of the tree is sensed to be a predeterminedminimum diameter, as described above. It is noted, however, that in theevent the diameter of the tree is such that the pin 344 does not moveout of engagement with the topping blade 310, the tree will not betopped in the embodiment of FIG. 12.

The mechanism to be described hereinbelow is contructed so that toppingwill be effected during the last portion of the extension of the boom,even though the diameter of the tree is somewhat larger than thepredetermined minimum diameter at which topping normally is effected.Moreover, in the construction to be described hereinbelow, the delimbingmechanism is moved to its open position during the end of the stroke ofthe boom 188 which carries the delimbing mechanism. Accordingly, themajor differences in the operation of the tree harvester to be describedhereinbelow and that of the tree harvester described in the embodimentsof FIGS. 1-20 is that the delimbing mechanism to be described below willbe moved to its open position during the end of the stroke of thedelimber, and, secondly, that the topping of the tree will be effectedat the end of the stroke of the topping mechanism, even though thediameter of the tree may be somewhat larger than the predeterminedminimum diameter at which topping normally occurs.

The construction shown in FIG. 21 is a schematic representation of themechanism which provides for opening of the delimbing arms 304, 306 atthe end of the outer stroke of the delimbing mechanism. As illustratedschematically in FIG. 21 the boom 188 which carries the delimbingmechanism moves into and out of the boom 190 in a telescoping relation,as described hereinabove. The boom 188 carries the delimbing mechanismon the outer end thereof. The delimbing mechanism, as describedhereinabove, includes a link 170 which is mounted for pivotal movementabout the pivot pin 174. As illustrated in FIG. 12, when the link 170 ismoved in a counterclockwise direction about the axis of the pivot pin174, the delimbing mechanism and delimbing arms are moved outwardly awayfrom each other to an open position. The mechanism shown schematicallyin FIG. 22 is designed to effect pivoting of the link 170 in such acounterclockwise direction in response to the delimbing mechanism movingthrough the last portion of its work stroke.

As the boom 188 and boom 190 move outwardly in a work stroke, the boom188 moves relative to the boom 190 in the last portion of the movementthereof, as should be understood from the pulley arrangement for movingthe booms, as disclosed and described hereinabove. When the boom 188begins moving relative to the boom 190, an angle member 500 which iscarried for movement with the boom 188 engages a stop 501 on the boommember 190. As a result, the boom 188 can continue to move outwardlyrelative to the angle member 500. The angle member 500 has a cable 502connected therewith, and the cable 502 is connected to a part 503 which,in turn, is connected to the link 170. The location at which part 503 isconnected to link 170 is illustrated in FIG. 12 in dotted lines. As theboom 188 moves, the pivot pin 174 for the link 170 continues to moveoutwardly therewith. However, since the angle member 500 is stopped fromoutward movement, the result is that the cable 502 prevents the portionof the link 170 to which it is connected from moving outwardly, and theresult is that the link 170 is pivoted about the pivot pin 174 in acounterclockwise direction, as shown in FIG. 12. The result of thisaction is that the delimbing arms are moved to an open position duringthe end of the stroke and more specifically, in response to thedelimbing mechanism moving through the last portion of its work stroke.When the boom 188 returns or moves in its return stroke, the relativemovement which occurred between the boom 188 and the angle member 500 isreversed and the angle member 500 is picked up by the boom 188 and movesalong the boom 188 away from the stop 501. As a result, the link member170 will rotate or return in a clockwise direction about the axis of thepin 174. However, nothing will be effected thereby in view of the factthat the tree may already have been dropped from the delimbing arms.

As noted above, the structure shown in FIGS. 22-25 also provides fortopping of the tree, even though the predetermined minimum diameter ofthe tree at which topping normally occurs has not been reached. This iseffected by mounting the pin 344 on the delimbing arms so that the pin344 can be moved a predetermined distance out of engagement with thetopping blade 310, even though the predetermined minimum diameter of thetree has not been reached, which would cause the pin 344 to move to aposition relative to the tree so that the topping blades 310, 312 wouldeffect topping of the tree, as described in connection with theembodiment of the tree harvester shown in FIG. 12.

The pin 344 in the embodiment of FIGS. 22-25 is moved in response to thedelimbing mechanism and topping mechanism moving through the last partof their work stroke when the booms are extended. The pin 344 has ashank portion 545 thereon which is connected with a link member 546. Aspring 547 biases the pin 344 toward the right, as viewed in FIG. 22.The pin 344 is secured to the delimbing arm 310 and moves radially ofthe tree inwardly in the direction of the arrow 548, illustrated in FIG.22, as the delimbing arm 310 moves radially inwardly due to thereduction of the diameter of the tree. The link 546 has a slidingconnection at 550 with a link member 551. The sliding connection at 550provides for and allows the link 546 to move radially inwardly of thetree with the pin 344. This can be more clearly in FIG. 24 wherein thepin 344 tends to move in the arc designated 560 as the diameter of thetree reduces and the link 546 slides relative to link 551 and movesbetween the positions illustrated in dotted and full lines in FIG. 24.

In this construction, the pivot shaft 174 for the delimber link 170 isextended so as to support the link 551 for pivotal movement relative tothe boom 188 about the axis of the shaft 174. It should be apparent, ofcourse, that upon pivoting movement of the link 551 about the axis ofthe shaft 174, the pin 344 will be moved to its dotted position,illustrated in FIG. 22. When in its dotted position, the pin 344 mayallow the topping blades 310, 312 to move into emgagement with the treeand effect topping thereof during the last portion of the work strokethereof.

The link 551 is moved about the axis of the pin 174 by a cable 570 whichis connected at one end to a connector 571 which, in turn, is connectedto the link 551. The cable 570 is connected at its other end, asillustrated in FIG. 25 to a connector 575. The connector 575, in turn,is pivotally connected to a link 576, which, in turn, is connected to apin 577 which extends transverse to the direction of movement of thebooms. The pin 577, more specifically, is carried by the boom 188 whichis the innermost boom and which moves outwardly relative to the boom 190during the last portion of the work stroke of the delimber, as describedabove.

The pin 577 has a link member 580 pivotally connected thereto at theside thereof opposite the side to which the link 576 is connected. Thisis best shown in FIG. 23. A roller 581 is carried by the link 580.

The roller 581 is adapted to engage a cam 582 which is fixedly connectedto the boom 180 at the outermost end thereof. When the roller 581 movesup the ramp 583 of the cam 582, the link 580 is moved in acounterclockwise direction, as illustrated in FIG. 25, which, in turn,effects a counterclockwise movement of the link 576, as illustrated inFIG. 25. The counterclockwise movement of the link 576 results in thecable 570 being moved in the direction of the arrow 590 in FIGS. 22 and25. As noted above, movement of the cable 570 in the direction of thearrow 590 will effect pivoting of the link 551 and a movement of the pin344 in a direction away from the topping blade 310. If the movementprovided is sufficient to cause the pin 344 to move out of engagementwith the topping blade 310, the topping blade will effect topping of thetree during the last portion of the stroke of the boom 188, as describedabove.

A suitable adjustment mechanism 595 is provided between the cable 590and the link 576. The adjustment mechanism 595 comprises a nut and screwarrangement and by relative movement therebetween, can effect theposition of the roller 581 relative to the ramp 583. In this manner, thedistance through which the roller moves can be adjusted, therebyadjusting the amount of movement of the pin 344.

Accordingly, the construction which provides for movement of the pin 344at the end of the work stroke, even though the pin is still inengagement with the topping blade 310 will result in topping of treeswhich are of a larger diameter than that which normally are toppedduring the major portion of the work stroke. Accordingly, the mechanismshown in FIG. 24 will effect topping of a tree when the delimbingmechanism, for example, encounters a 3-inch diameter portion of thetree, even though the delimbing mechanism and topper have not reachedthe end of their stroke. This is effected because the pin 344, in such acase, moves radially inwardly toward the tree a sufficient distance toallow the topping blades 310, 312 to engage the tree, as described abovein connection with the modification shown in FIG. 12. However, theconstruction shown in FIG. 24 also will provide for topping of a treebetween a 3-inch diameter and a 5-inch diameter, for example, at the endof the work stroke of the booms. This is effected because, even thoughthe pin 344 has not moved radially inwardly of the tree to a positionwhich would allow the topping blades 310, 312 to engage the tree andeffect topping thereof, the pin 344 is moved generally longitudinally ofthe boom by the mechanism shown in FIGS. 22, 25 so as to move away fromthe topping blade 310. This movement will be sufficient to cause thetopping blades 310, 312 to top a tree which is of a greater diameterthan that at which normal topping is effected, but will not besufficiently great so as to effect topping of a tree which is of toolarge a diameter, such as greater than 5 inches. Accordingly, thismechanism will effect topping of a tree at the end of the stroke of thedelimbing mechanism, which is greater than that at which normal toppingis effected, but which is of a diameter less than that which it capableof topping.

Having described a specific preferred embodiment of the invention, thefollowing is claimed:
 1. Apparatus for use in association with a vehiclefor harvesting and transporting trees, said apparatus comprising a clampassembly comprising a pair of arms adapted to be mounted on the vehiclefor gripping logs to be transported, said pair of arms being operablebetween a closed condition in which the logs are held against a lowerportion of said clamp assembly to retard relative movement between thelogs and the vehicle while the logs are being transported and an opencondition in which the logs are released, and a roller mounted on theframe of said clamp assembly and movable upwardly against the logs forraising the logs off said lower portion of said clamp assembly inresponse to operation of said arms from said closed condition to saidopen condition to thereby facilitate disengaging the logs from saidclamp assembly.
 2. Apparatus for use in association with a vehicle forharvesting and transporting trees; said apparatus comprising a clampassembly adapted to be mounted on the vehicle for gripping logs to betransported, said clamp assembly being supported by a pivotal frame andoperable between a closed condition in which the logs are held against alower portion of said clamp assembly to retard relative movement betweenthe logs and the vehicle while the logs are being transported and anopen condition in which the logs are released; a support memberoperatively connected to said clamp assembly; and means for pivotingsaid frame in response to operation of said clamp assembly to the opencondition to raise said support member to lift the logs off the lowerportion of said clamp assembly.
 3. Apparatus as set forth in claim 2wherein said frame includes an arcuate lower surface which is adapted tobe rockably disposed on a generally planar support surface of thevehicle, said means for pivoting said frame including a member forpressing against the vehicle to rock said frame in response to operationof said clamp assembly to the open condition to thereby move saidsupport member and logs upwardly.
 4. Apparatus as set forth in claim 2further including knife edge means located on the lower portion of saidclamp assembly for penetrating and securely engaging at least some ofthe logs gripped by said clamp assembly when said clamp assembly is inthe closed condition, said means for raising the logs being operable todisengage the logs from said knife edge means in response to operationof said clamp assembly to the open condition.